DATA SEGMENT
DATA ENDS
STACK SEGMENT STACK 'STACK'
	DB 100H DUP(?)
STACK ENDS
CODE SEGMENT             
    ASSUME CS:CODE, DS:DATA, SS:STACK
DELAY PROC
	MOV BX, 5
LLL:
	MOV CX, 0
LL:
	LOOP LL
	DEC BX
	JNE LLL
	RET
DELAY ENDP
START:
    PUSH DS
    XOR AX, AX
    PUSH AX
    MOV AX, DATA
    MOV DS, AX
    MOV CX, 200H
AGAIN:
    MOV DX, 210H
    OUT DX, AL
    CALL DELAY
    MOV DX, 270H
    OUT DX, AL
    CALL DELAY
    LOOP AGAIN
    MOV AX, 4C0H
    INT 21H
CODE ENDS
END START